S3 Focus Help/Advice

[KonNic]

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Hey Guys,

recently got a used S3 and having hit and miss with auto focus says it’s on point but always seams to be just a bit off when manuel focusing can get image with crisp focus. 

wanted to see if any one has had that happen to them, is it normal or should I send body for CLA, Lens or both 

Edited August 24, 2024 by KonNic

[Milan_S]

Try using 2 times the F stop as a minimum set the S3 to MF but use the back button focus. The S3 AF is not the most accurate certainly when used wide open. I can use MF like a champ with the M series but with the S i mostly rely on AF with back button focus and I have found some issues using the Summicron-S 100 mm f2 because of the minimal DOF. Did you try the S3 with multiple lenses? 

[Stuart Richardson]

My S3 was also very slightly off with manual focus. I talked to Leica about it and they said that it was normal for it to be slightly off. It was not an answer I felt was acceptable, but it was the one that was given. I think the tolerances required for the placement of the focusing screen are extremely tight at 64mp, such that it may not necessarily be easy to keep it 100% accurate, especially when wide open and close up. In general, I found that I used live view to get the best focus in critical compositions. 

Regarding AF, there are a lot of threads about it in the S system cameras with advice, complaints and theories. I did about seven years with the S2 and S006, and a year with the S3. I got used to the AF enough to get what I wanted out of it most of the time. I never found that the OVF was good enough for absolute accuracy (talking 100x150cm prints, for the web or small prints it was fine).

There is only the one central focusing point, and the AF sensor is not the point of the cross in the VF, it is more or less the entire area under the circle. So sometimes the camera will just choose something it wants within the circle, even if that is not what you want. It usually goes for the closest, higher contrast feature. For example, if the circle covers most of someone's head, but the cross is on an eye, it still might choose an ear or nose. It generally does not, but it can. Unfortunately the focusing system in the S cameras was locked to about 2007 era medium format SLR level, and they never really changed it much.

Your camera may be helped by a CLA, but my guess is that it may not. I think AF has always been a challenge in the S cameras, and much of it is a learning curve about figuring out how the camera works..

[KonNic]

Here a few quick test shots on tripod I own two lenses the 70mm & 100mm, the 120mm focus motor gave out  at least still good on Manuel. Waiting on a 24mm to arrive 

the control photo of cross hairs for each shot 

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70mm 2.8f AF

70mm 5.6f AF

70mm 2.8f MF

70mm 5.6f MF

 

 

Edited August 24, 2024 by KonNic

[KonNic]

100mm 2f AF

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100mm 5.6f AF

100mm 2f MF

100mm 5.6 MF

[KonNic]

Also cropped files 

70mm 5.6 AF/MF

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70mm 2.8f AF/MF

[KonNic]

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Cropped 

100mm 2f AF/MF

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100mm 5/6f AF/MF

[KonNic]

Let me know guys if it’s better to try real subject, also can try the S lenses on SL2 & SL2-S if needed 

[Pieter12]

The differences really seem either undetectable or very slight. Too much pixel-peeping. If this annoys you, you need a different, maybe more modern camera. Go out and take some pictures!

[KonNic]

I’ve shot a fair bit with the S3 already. And it’s bin hit and miss with getting subjects in focus, having their face &/or eyes come out of focus is really annoying. That my main problem. As I borrowed an S007 previously and feel I was having a better hit rate, then current S3. That’s why I am asking if people think a CLA is worth doing on the camera or lens or both 

[KonNic]

Here’s a crop of a portrait taken recently

LEFT: just +\- out of crisp focus.  
 

RIGHT: bang on eye focus gives subject pop.

Yes I am pixel peeping here but this difference can be clearly seen when printed. 

Am I being to picky ? To have consistent focus. 

 

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[Pieter12]

Have you tried sharpening in C1 or Topaz AI? Once again, probably because of the limits imposed by posting on the internet, I see a slight but not significant difference. Also AF is not a necessity, especially for a slow camera like the Leica S. MF works just fine. As I mentioned earlier if fast, accurate AF is important to you, you might want to consider a more modern camera.

Edited August 24, 2024 by Pieter12

[KonNic]

The upload limited are definitely not helping with the image difference. 
 

I don’t mind the speed of the AF at all it’s the miss rate that’s the problem for me. I don’t have the 007 to compare again but it definitely seamed to be nailing focus more consistently. 

Even being slight out of focus I still love the how the images look and colors pop. 

My concern Is there something in the body of the camera that can be missing nailing the focus, as when I use the S lens on the SL2/SL2S they seam to be fine 

[Stuart Richardson]

What focus mode are you using? AFs? Back button focus in MF mode? Certainly you will want to avoid AFc, but I assume you are. One thing that I found helped when I was shooting the S cameras was to refocus fairly frequently. Take your finger off the shutter and refocus, or press the back button more than once. I found that sometimes the S cameras would get close but not perfect on the first half press or button focus, but pressing it again would cause the camera to fine tune the focus and it would be more accurate.

I don't agree that the S quite as bad about focus as Pieter is making it sound, but it is certainly not like the SL2 or most modern cameras. I would reiterate what I said about making the entire circle of the AF patch cover something equidistant to what you want in focus. Obviously it is not always possible, but if you point the S at a flat textured surface equidistant to the camera that fills the whole AF patch, it rarely misfocuses (I realize this is not saying much for its abilities). I say this because there are two separate issues: 1. Did the camera miss focus because it could not focus on what was in the AF circle? or 2. Did it achieve focus correctly, just not on the intended point. Unlike more sophisticated pattern recognition focusing systems, the S is not looking for irises or faces etc, it is just looking at contrast and generally it prioritizes things closer to the camera.

I suspect that your camera might be performing as well as it is capable, but that it is so much less capable than a contrast detect system like the one in the SL2 or a modern system like those in the Sony and Canon cameras, for example. The S AF system is nearly twenty years old. I found the best course of action was to try to present the camera as clear an AF target as possible, often via focus and recompose, and then "trust but verify" by continuously taking at least two or three photos refocusing each time.

A lot of this stuff is why we don't have DSLR's anymore...it is very hard to achieve consistent perfect accuracy with phase detect sensors alone on high resolution bodies with lenses that have shallow DOF and high levels of sharpness. Any slight misfocus becomes very visible.

[KonNic]

I am using manual focus with back button, will try with multi hit BB focusing.

I would also second that, especially when I tried the 007 and had much better focus hits. I don’t think AF was down graded on the S3. I get what your saying about the focus circle but to me it seams like my camera is missing focus completely like actual focusing outside of that circle. 
 

I've reach out to Leica HO to see what they would recommend. Let’s see how long it’s going to take to get a replay. 

[epines]

I have an S3, and I feel like my experience with focusing has been very good. I use AF (back button) all the time. I find it gives better exact focus than manual focus. The lenses are also all very sharp at their widest apertures. (Although the 100mm might not be, as it's a different design; not sure; I don't have it. The 100mm is also known for hunting for focus a bit more than the others, from what I've read.)

I'm happy post a focus test similar to yours here, but it might take me a few days. A bit buried right now.

Can you test your S3 against another one, either owned by someone nearby or at a dealer? I feel like you should be getting a bit better with AF.

That being said, it does miss sometimes. As others have said, it tends to lock on to the highest-contrast item in the center (but not necessarily the closest item, in my experience). FYI -- I've been told by Leica that the AF area isn't the central circle, but the imaginary circle formed around the edges of the center crosshairs.

For a focusing test, it would help if there weren't other confusing visuals around your desired focus point (the plants just behind the Russian doll could confuse the system). Have you tried focusing, say, on a bunch of books on a shelf, where all the spines are in the same plane?

 

[KonNic]

I will take some book and flat service photos with leas destructions.

Side question for you @epines my GPS decided it no longer wants to connect ether how’s yours been? 

Would appreciate see your focus photos as well when you get a chance 

[Pieter12]

12 minutes ago, KonNic said:

I will take some book and flat service photos with leas destructions.

Side question for you @epines my GPS decided it no longer wants to connect ether how’s yours been? 

Would appreciate see your focus photos as well when you get a chance 

The GPS on my S3 can take a while to lock on and give a position.

If you want to check critical focus, you would be better off shooting the books wide open and from an angle, focusing on a particular spine. Upon examination, check to see if that spine is indeed in focus. Or use a chart like this, positioned at about 45% from the camera/lens axis. Once again, wide open and focused on the center line and verify it.

Focus chart.pdf

Edited August 28, 2024 by Pieter12

[KonNic]

Will give this a go

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[epines]

The drawback of shooting a row of books from an angle is, if the resulting focus doesn't end up on the spine / book you intended, there's no way to know if it's due to the camera choosing the wrong book (which can definitely happen with the S, when it has multiple similar options in the crosshairs area), or if it's due to the camera's focus being out of alignment.